Several electronics questions
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Posts: 46,084
I can think of two questions I have right now, but by the time I get to the
end of this email, I will most likely have thought of more [noparse]:)[/noparse]
1) How big a motor can I run off a stamp pin connected to an NPN transistor?
I have two 600ma motors (one for each side, tank steering) for my robot. I
was originally planning on connecting the transistors to some relays to
control the motors, but that is simple on/off. I want some speed control.
Can I use the transistor to do that directly? Do something like PULSOUT
PIN, SPEED (I forget the real syntax, hopefully that is close) and have it
run at less than full speed? How would I reverse it? (aka go backwards [noparse]:)[/noparse])
2) If I use serial commands in PBASIC to make my "brain" stamp talk to my
motor control stamp, is there enough power in the connection so I can run an
LED with a 470ohm resistor (so I can see when they are talking)? I am going
to try to make an ASCII curcuit diagram to show what I mean:
RESISTOR LED
+---^^^----|<
+
| |
BSII pin +
+
+
+ other BSII pin
I actually don't even know if I can hook stamps up that way... I got a
rather vague answer from parallax tech support, and this forum didn't give
me an answer at all [noparse]:)[/noparse] I could put the LED "inline" instead of having it be
a side thingy. Because of the resistor on that side curcuit, I bet the
electricity will go right past it...
3) I thought of another question because of the joystick sitting on my
computer desk. If I want to control my robot with it (via a radio link),
how do I read the pots inside it? Do I need an ADC? I have never used one
of those and find them somewhat daunting. I know my joystick has just a
couple of pots inside because it is the same exact type that is used by
every FIRST robotics team in the world. It is a no-name company product
labled "FlightStick". The robotics team I am on regularly chops their
joysticks apart. They have the advantage of just being able to plug it into
the Operator Interface device, and that into a radio-modem to get the
numbers to appear magically in the program on the robot... A related
problem is where can I buy a gameport connector? I can find DB9s and 15-pin
parallel ports at radioshack, but I have never seen a gameport before.
If you read through all my ignorance and still feel like giving me a reply,
I could certainly use it! Thanks.
______________________________________________
FREE Personalized Email at Mail.com
Sign up at http://www.mail.com/?sr=signup
end of this email, I will most likely have thought of more [noparse]:)[/noparse]
1) How big a motor can I run off a stamp pin connected to an NPN transistor?
I have two 600ma motors (one for each side, tank steering) for my robot. I
was originally planning on connecting the transistors to some relays to
control the motors, but that is simple on/off. I want some speed control.
Can I use the transistor to do that directly? Do something like PULSOUT
PIN, SPEED (I forget the real syntax, hopefully that is close) and have it
run at less than full speed? How would I reverse it? (aka go backwards [noparse]:)[/noparse])
2) If I use serial commands in PBASIC to make my "brain" stamp talk to my
motor control stamp, is there enough power in the connection so I can run an
LED with a 470ohm resistor (so I can see when they are talking)? I am going
to try to make an ASCII curcuit diagram to show what I mean:
RESISTOR LED
+---^^^----|<
+
| |
BSII pin +
+
+
+ other BSII pin
I actually don't even know if I can hook stamps up that way... I got a
rather vague answer from parallax tech support, and this forum didn't give
me an answer at all [noparse]:)[/noparse] I could put the LED "inline" instead of having it be
a side thingy. Because of the resistor on that side curcuit, I bet the
electricity will go right past it...
3) I thought of another question because of the joystick sitting on my
computer desk. If I want to control my robot with it (via a radio link),
how do I read the pots inside it? Do I need an ADC? I have never used one
of those and find them somewhat daunting. I know my joystick has just a
couple of pots inside because it is the same exact type that is used by
every FIRST robotics team in the world. It is a no-name company product
labled "FlightStick". The robotics team I am on regularly chops their
joysticks apart. They have the advantage of just being able to plug it into
the Operator Interface device, and that into a radio-modem to get the
numbers to appear magically in the program on the robot... A related
problem is where can I buy a gameport connector? I can find DB9s and 15-pin
parallel ports at radioshack, but I have never seen a gameport before.
If you read through all my ignorance and still feel like giving me a reply,
I could certainly use it! Thanks.
______________________________________________
FREE Personalized Email at Mail.com
Sign up at http://www.mail.com/?sr=signup
Comments
Here are some asnwers that may point you in the proper direction.
1) The amount of current you can control from from your NPN transistor is
determined by the type and packaging of the transistor as well as any heat
sinking that you may be using. For example, a small 2N2222A in a TO-92
(small plastic package) cannot handle as much as 2N3055 in TO-3 (large steel
package), even though they are both NPN transistors. As far as analog speed
control, I guess you could use the PWM out with some smoothing (RC network)
before it hits the driver trasnisitor. As far as reverse, I would think that
DPDT relays wired to crossover (i.e. switch the + and - terminals of the
motor) would be an effective solution. You can drive the relay coil quite
easily with a 2N222A transistor, just be sure to use a snubbing diode across
the relay coil to protect everything when the circuit is de-energized.
As far as an indication LED on the line between the BS2 chips, you can use
the following circuit to eliminate any problems with loading
line between stamps
*
|
| +5V
| |
| |
| |collector
| /
| 4.7k b|/
|----/\/\/\----|
|\
\emitter
|
|
|
__
\/ led
----
|
|
/
\ 470 ohm
/
\
|
| ground
Regarding the joystick connectors, they are available from radio shack if
you order them thru their commercial catalog. However, a joystick does not
use all 15 contacts in the joystic connector, If fact, the 15 pin connector
is intended to support 2 joysticks. if you wish to "dedicate" your joystick
to the use of your robot, you could cut the exisiting connector off and
replace it with a commonly available DB-9 connector, or if you wanted to use
it for PC's also, you could cut the cable about 4" away from the existing
DB-15 connector and splice in a pair of DB-9's (male and female connector
pair, male side on the joystick side of the cable, female on the DB-15 side
of the cable). That way, you could leave the DB-15 side connected to your
computer, and disconnect the joystick and hook it up to your robot. As far
as the use of control, you could use the POT commands quite easily.
Original Message
From: Yanroy [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=2ivWRx6h3Gj4M71xjo4InFa7Vnd7cvKU1qRTvKhPCPMxQgEAC305wZnCcOLiuMci68Z4ikY1]yanroy@u...[/url
Sent: Saturday, January 06, 2001 8:35 PM
To: BASIC Stamp Forum
Subject: [noparse][[/noparse]basicstamps] Several electronics questions
I can think of two questions I have right now, but by the time I get to the
end of this email, I will most likely have thought of more [noparse]:)[/noparse]
1) How big a motor can I run off a stamp pin connected to an NPN transistor?
I have two 600ma motors (one for each side, tank steering) for my robot. I
was originally planning on connecting the transistors to some relays to
control the motors, but that is simple on/off. I want some speed control.
Can I use the transistor to do that directly? Do something like PULSOUT
PIN, SPEED (I forget the real syntax, hopefully that is close) and have it
run at less than full speed? How would I reverse it? (aka go backwards [noparse]:)[/noparse])
2) If I use serial commands in PBASIC to make my "brain" stamp talk to my
motor control stamp, is there enough power in the connection so I can run an
LED with a 470ohm resistor (so I can see when they are talking)? I am going
to try to make an ASCII curcuit diagram to show what I mean:
RESISTOR LED
+---^^^----|<
+
| |
BSII pin +
+
+
+ other BSII pin
I actually don't even know if I can hook stamps up that way... I got a
rather vague answer from parallax tech support, and this forum didn't give
me an answer at all [noparse]:)[/noparse] I could put the LED "inline" instead of having it be
a side thingy. Because of the resistor on that side curcuit, I bet the
electricity will go right past it...
3) I thought of another question because of the joystick sitting on my
computer desk. If I want to control my robot with it (via a radio link),
how do I read the pots inside it? Do I need an ADC? I have never used one
of those and find them somewhat daunting. I know my joystick has just a
couple of pots inside because it is the same exact type that is used by
every FIRST robotics team in the world. It is a no-name company product
labled "FlightStick". The robotics team I am on regularly chops their
joysticks apart. They have the advantage of just being able to plug it into
the Operator Interface device, and that into a radio-modem to get the
numbers to appear magically in the program on the robot... A related
problem is where can I buy a gameport connector? I can find DB9s and 15-pin
parallel ports at radioshack, but I have never seen a gameport before.
If you read through all my ignorance and still feel like giving me a reply,
I could certainly use it! Thanks.
______________________________________________
FREE Personalized Email at Mail.com
Sign up at http://www.mail.com/?sr=signup
Well.... You have several questions...
Here are some asnwers that may point you in the proper direction.
1) The amount of current you can control from from your NPN transistor is
determined by the type and packaging of the transistor as well as any heat
sinking that you may be using. For example, a small 2N2222A in a TO-92
(small plastic package) cannot handle as much as 2N3055 in TO-3 (large steel
package), even though they are both NPN transistors. As far as analog speed
control, I guess you could use the PWM out with some smoothing (RC network)
before it hits the driver trasnisitor. As far as reverse, I would think that
DPDT relays wired to crossover (i.e. switch the + and - terminals of the
motor) would be an effective solution. You can drive the relay coil quite
easily with a 2N222A transistor, just be sure to use a snubbing diode across
the relay coil to protect everything when the circuit is de-energized.
........
<<
What is an RC network? From the context I take it that an RC network
generate an analog voltage from a PWM signal. Does it make a flat voltage,
or just take the sharp edges off the stamp's wave? The way I understand
transistors, the more power you put in through the control pin (I always get
the technical terms mixed up...) limits the flow through the other two pins.
I am a bit unclear if this limits the voltage or the current. If it limits
the voltage then I lose torque rapidly (quadraticly?), while if it is
current, I the torque/speed line gets truncated... I am not sure if there is
a difference, I am just racking my brain for what I remember about how a
motor responds to cuts in voltage and current. I do know for a fact that if
I am dumping voltage, I am creating lots of heat and consuming a fixed
current while getting less torque. If I could put a PWM directly on the
motor, the on/off very rapidly would maximize torque while reducing speed
and conserve power. If the transistor can switch fast enough (and I think
it can, since they power the computer I am typing on now), wouldn't it make
more sense to not smooth it at all? I am probably completely mixed up. If
someone would care to straigten me out...
PS - If anyone knows how to weld/solder aluminum with a torch that can reach
about 1300 degrees celsius, please tell me that too. It can go above the
melting point of aluminum, yet I can't seem to liquify it and make the two
parts run together. I probably need some kind of solder. What do I need
and where do I get it? This is a major problem because if I don't have a
frame, I don't have more than an assortment of spinning motors on my
workbench [noparse]:)[/noparse] Thanks for your time.
______________________________________________
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Sign up at http://www.mail.com/?sr=signup
contact. Then the proper method will be use an inert gas to protect the
metal.
Argon + arc + special electrodes is the most used method for aluminium
welding.
ACJacques
Yanroy wrote:
>
> >>
> Well.... You have several questions...
> PS - If anyone knows how to weld/solder aluminum with a torch that can reach
> about 1300 degrees celsius, please tell me that too. It can go above the
> melting point of aluminum, yet I can't seem to liquify it and make the two
> parts run together. I probably need some kind of solder. What do I need
> and where do I get it? This is a major problem because if I don't have a
> frame, I don't have more than an assortment of spinning motors on my
> workbench [noparse]:)[/noparse] Thanks for your time.
>
> ______________________________________________
> FREE Personalized Email at Mail.com
> Sign up at http://www.mail.com/?sr=signup
using a propane torch, POSSIBLY a welding store would sell this rod. I am a
welder myself and
have my doubts about how well this welding rod actually works. I beleive
Northern Hydraulics sells this special welding rod.
The argon, arc etc etc listed is the correct method of course.
At 04:01 PM 1/9/2001 -0200, you wrote:
>Welding aluminium is not easy since it quickly oxidize with air (oxigen)
>contact. Then the proper method will be use an inert gas to protect the
>metal.
>Argon + arc + special electrodes is the most used method for aluminium
>welding.
>ACJacques
>
>
>Yanroy wrote:
>>
>> >>
>> Well.... You have several questions...
>
>> PS - If anyone knows how to weld/solder aluminum with a torch that can reach
>> about 1300 degrees celsius, please tell me that too. It can go above the
>> melting point of aluminum, yet I can't seem to liquify it and make the two
>> parts run together. I probably need some kind of solder. What do I need
>> and where do I get it? This is a major problem because if I don't have a
>> frame, I don't have more than an assortment of spinning motors on my
>> workbench [noparse]:)[/noparse] Thanks for your time.
>>
>> ______________________________________________
>> FREE Personalized Email at Mail.com
>> Sign up at http://www.mail.com/?sr=signup
>
>
>
>
Sincerely
Kerry
Admin@M...
WWW server hosting [url=Http://mntnweb.com]Http://mntnweb.com[/url]
Kerry Barlow
p.o. box 21
kirkwood ny
13795
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Hash: SHA1
Consider using a MAPP gas and Oxygen torch (about $40 at
any hardware store). A few thousand degrees makes a BIG
difference!
>
Original Message
> From: Kerry Barlow [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=GabJDbbw1nCkVhslM_SY6wCMXbmkb4vN_J5uPHFhxEuzDIfFPEjWV630ANS4ZySfJdPyEMev8GtDXQ]admin@m...[/url
> Sent: Tuesday, January 09, 2001 12:11 PM
> To: basicstamps@egroups.com
> Subject: Re: [noparse][[/noparse]basicstamps] RE: Several electronics questions
>
>
> I have seen catalogs selling special rod for welding pot
> metal and aluminum,
> using a propane torch, POSSIBLY a welding store would sell
> this rod. I am a
> welder myself and
> have my doubts about how well this welding rod actually
> works. I beleive
> Northern Hydraulics sells this special welding rod.
> The argon, arc etc etc listed is the correct method of course.
>
>
> At 04:01 PM 1/9/2001 -0200, you wrote:
> >Welding aluminium is not easy since it quickly oxidize with
> air (oxigen)
> >contact. Then the proper method will be use an inert gas to
> protect the
> >metal.
> >Argon + arc + special electrodes is the most used method for
> aluminium
> >welding.
> >ACJacques
> >
> >
> >Yanroy wrote:
> >>
> >> >>
> >> Well.... You have several questions...
> >
> >> PS - If anyone knows how to weld/solder aluminum with a
> torch that can reach
> >> about 1300 degrees celsius, please tell me that too. It
> can go above the
> >> melting point of aluminum, yet I can't seem to liquify it
> and make the two
> >> parts run together. I probably need some kind of solder.
> What do I need
> >> and where do I get it? This is a major problem because if
> I don't have a
> >> frame, I don't have more than an assortment of spinning
> motors on my
> >> workbench [noparse]:)[/noparse] Thanks for your time.
> >>
> >> ______________________________________________
> >> FREE Personalized Email at Mail.com
> >> Sign up at http://www.mail.com/?sr=signup
> >
> >
> >
> >
> Sincerely
> Kerry
> Admin@M...
> WWW server hosting [url=Http://mntnweb.com]Http://mntnweb.com[/url]
> Kerry Barlow
> p.o. box 21
> kirkwood ny
> 13795
>
>
>
>
>
>
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fabrication of tanks, and similar joining of thin sections.
Low-pressure regulators, tips, and special flux is used.
The flux produces a brilliant yellow light when heated,
requiring a special filter lense. Gas-welding produces a
less brittle weld than electric arc techniques.
Aluminum shielded-arc "stick" electrode is also available.
It comes with a noticeable learning curve [noparse]:)[/noparse]
All techniques require close attention to preheat, due to
the high thermal conductivity and coefficient of expansion
of aluminum. The TIG method mentioned below is easiest to
learn, but requires a significant investment in equipment.
regards, Jack
A.C.Jacques wrote:
>
> Welding aluminium is not easy since it quickly oxidize with air (oxigen)
> contact. Then the proper method will be use an inert gas to protect the
> metal.
> Argon + arc + special electrodes is the most used method for aluminium
> welding.
> ACJacques
>
> Yanroy wrote:
> >
> > >>
> > Well.... You have several questions...
>
> > PS - If anyone knows how to weld/solder aluminum with a torch that can reach
> > about 1300 degrees celsius, please tell me that too. It can go above the
> > melting point of aluminum, yet I can't seem to liquify it and make the two
> > parts run together. I probably need some kind of solder. What do I need
> > and where do I get it? This is a major problem because if I don't have a
> > frame, I don't have more than an assortment of spinning motors on my
> > workbench [noparse]:)[/noparse] Thanks for your time.
> >
> > ______________________________________________
> > FREE Personalized Email at Mail.com
> > Sign up at http://www.mail.com/?sr=signup
>>contact. Then the proper method will be use an inert gas to protect the
>>metal.
True, but if you brush it clean with a stainless steel brush IMMEDIATELY
prior to welding, it can be done. Very tricky, though. It goes almost
no warning before it turns to goo (no nice color changes as with steel).
-Carl
To: BASIC Stamp Forum <basicstamps@egroups.com>
Date: Tue, 9 Jan 2001 12:25:29 -0500 (EST)
>PS - If anyone knows how to weld/solder aluminum with a torch that can reach
>about 1300 degrees celsius, please tell me that too. It can go above the
There's a UK company who produce a kit to allow brazing aluminium, it's usually
available from model shops. You can repair alu crankcases on aero engines and
so on. Success would depend on the size of your project I'd guess.
--
Regards,
Derryck Croker